1. Field of the Invention
This invention relates to an apparatus for treatment of a material with a liquid, for example in the separation of one or more substances from a mixture of two or more substances using a solvent selective for at least one substance in the mixture.
2. Description of the Prior Art
There are many procedures in which a material is treated with a liquid and in which it is desirable for the material to be thoroughly treated by all the available liquid. For example, in laboratory procedure it is often desired to separate mixtures of substances or to purify an impure substance by solvent separation in which the mixture or substance to be treated is contacted with solvent in which at least one of the substances to be separated, an impurity or a substance to be purified is selectively soluble. Another example is in laboratory scale experimental dyeing techniques.
It would be desirable to provide an apparatus for at least partially automated convenient and efficient performance of such techniques.
In applicant's U.S. Pat. No. 4,680,112 and its equivalent European patent application published under No. 0148629 there is described an apparatus which attempts to provide such an improved way of separating a mixture of substances with a liquid, for example in the purification of an impure substance. The apparatus is a vortex-type liquid treatment device and its essential features are that it has therein a substantially cylindrical chamber and contains means to form liquid in the apparatus into a vortex. Within the chamber is held a receptacle for the material to be treated and there is arranged means to receive liquid from the vortex and conduct the liquid to outlet means above material in the receptacle and from which the liquid pours on the material. The bottom of the receptacle is permeable to the liquid, which flows from the receptacle to re-enter the vortex and be recycled. Preferably in such apparatus the container comprises a bottom portion and a lid portion. Further the means for driving the vortex generally comprises stirring means, and a third preferred feature is that the liquid receiving means comprises a duct member suspended across the interior of the chamber, the ends of the duct member each having an inlet disposed for ingress into the duct member of liquid forming a vortex and the duct member comprising the outlet above the bottom wall of the receptacle.
In the specific vortex-type apparatus of U.S. Pat. No. 4,680,112 there is an internal sleeve in the chamber which sits on the bottom wall of the apparatus. At the top of the sleeve there are spokes which extend radially inwardly to the receptacle which is held thereby. The means for receiving liquid from the vortex comprises a duct extending across the chamber with openings at its ends for ingress of liquid and a slit in the bottom thereof disposed above the interior of the receptacle, the openings being arranged for inflow of liquid from the vortex.
Applicant's apparatus described above has been found to be effective in practice as well as relatively easy, and hence economical, to make. Nothwithstanding these advantageous features, it has now been appreciated that the successful operation of the apparatus could be made even more efficient and that its manufacture can be further simplified.
One operational improvement which has been perceived resides in improving the flow of the vortex. Observation of applicant's earlier apparatus has shown that the vortex is satisfactorily driven to the diametric duct, but it is now realised that interference of the inner sleeve and the spokes decreases the efficiency of operation. However, perception of this opportunity for improvement raised the further problem of providing a solution which still enabled ready manufacture.